old Jack that no Germans had visited the Chateau;
that the marquis was busy all day with his machinery, and never
left his turret except to eat at daylight in the grand salon
below. He also intimated that his master was about ready to make
another ascension in the new balloon, which, old Pierre affirmed,
had a revolving screw at either side of the wicker car, like a
ship; and, like a ship, it could be steered with perfect ease. He
even took Jack to a little stone structure that stood in a
meadow, surrounded by trees. In there, according to Pierre, stood
this marvellous balloon, not yet inflated, of course. That was
only a matter of five seconds; a handful of the silver dust
placed at the aperture of the silken bag, a drop of pure water
touched to it, and, puff! the silver dust turns to vapour and the
balloon swells out tight and full.

Jack had peeped into the barred window and had seen the wicker
car of the balloon standing on the cement floor, filled with the
folded silken covering for the globe of the balloon. He could
just make out, on either side of the car, two twisted twin
screws, wrought out of some dull oxidized metal. On returning to
Morteyn that evening he had told Lorraine.

She explained that the screws were made of a metal called
aluminum, rare then, because so difficult to extract from its
combining substances, and almost useless on account of its being
impossible to weld. Her father, however, had found a way to
utilize it--how, she did not know. If this ascension proved a
success the French government would receive the balloon and the
secret of the steering and propelling gear, along with the
formula for the silvery dust used to inflate it. Even she
understood what a terrible engine of war such an aerial ship
might be, from which two men could blow up fortress after
fortress and city after city when and where they chose. Armies
could be annihilated, granite and steel would be as tinder before
a bomb or torpedo of picric acid dropped from the clouds.

On the 10th of August, a little after five o'clock, Jack left
Lorraine on the terrace at Morteyn to try once more to see the
marquis--for Lorraine's sake.

He turned to the west, where the last Uhlan of the rear-guard was
disappearing over the brow of the hill, brandishing his pennoned
lance-tip in the late rays of the low-hanging sun.

"Good-by," he said, smiling up at her from the steps. "Don't
worry, please don't. Remember your father is well, and